CN103916220A - Network coding cooperative communication method based on polarization codes - Google Patents

Abstract

The invention discloses a network coding cooperative communication method based on polarization codes, and belongs to the technical field of network coding. The method comprises the following steps of constructing a polarization code generation matrix GP, setting polarization code parameters N and K based on the number of relay nodes of the network and the number of users, and constructing a polarization code generation matrix GP again based on N and K, wherein N expresses the code length, K expresses the length of information bits, each column of the matrix GP corresponds to one relay node, and each row of the matrix GP corresponds to one user; receiving information sent by the users through the corresponding relay nodes based on the matrix GP; when the jth column and the ith row of the matrix GP are 1, receiving the information sent by the user corresponding to the ith row through the relay node corresponding to the jth column; carrying out binary domain addition on the received information by the relay nodes, and then sending the information to a receiving end; arranging the N received relay information rj in sequence by the receiving end to form a polarization codeword, and carrying out coding on the polarization codes. The method is used for the network coding, and can reduce transmission error rate and improve the network transmission stability.

Description

A kind of network encode collaboration communication method based on polarization code

Technical field

The present invention relates to the network cooperation communication of network code, be specifically related to a kind of network encode collaboration communication method based on polarization code.

Background technology

In the research of network, usually represent the structure of communication network with directed graph, utilize " minimal cut max-flow " theorem in Graph Theory known, the namely minimal cut of this figure of the maximum stream flow that this figure (communication network) can transmit.The mode of traditional network trunk storage forwarding can not meet the realization of this point.And in communication network Adoption Network coding techniques, namely at via node place to the information technology forwarding of encoding again, at receiving terminal, each destination node translates information needed according to coding rule by certain method, just greatly degree improves the transmission rate of network, reduce the access times to channel, more fully utilized efficiently the link circuit resource of communication network, finally realized the theoretical attainable maximum information transmission rate upper limit in graph theory.

Adoption Network coding techniques in communication network, can improve the rate of information throughput on the one hand, helps to reach the network capacity of communication network; On the other hand, network coding technique also has in a lot of technical fields such as reduction network in general energy consumption and load balancing the effect can not be ignored, and has improved to a great extent the overall performance of communication system.But at transmission error rate, also there is certain defect in current existing network code mode, can not meet preferably practical engineering application demand on transmission stability.

Summary of the invention

Goal of the invention of the present invention is: will be applied to network coding cooperation communication for the polarization code of channel error correction, a kind of network encode collaboration communication method based on polarization code is provided, to reduce the transmission error rate in network coding cooperation communication excessively, improve Internet Transmission stability.

Network encode collaboration communication method based on polarization code of the present invention, comprises the following steps:

Step 1: structure polarization code generator matrix G _p:

Determine hyper polarization code parameters N, K, wherein, N represents code word size, K represents information bit length:

Described polarization code Parameter N is more than or equal to user's number m and is less than the minimum value of the via node number that network provides, and N=2 ⁿ, n is positive integer;

Described polarization code parameter K equals user's number m;

And user's number m is less than or equal to the via node number of current network;

Based on described polarization code Parameter N, K structure polarization code generator matrix G _p, described matrix G _pthe corresponding via node of every row, the corresponding user of every a line;

Step 2: each via node is based on matrix G _preceive the information that respective user sends: as matrix G _pwhen j is listed as i behavior " 1 ", is listed as corresponding via node with j and receives the message sending with the capable corresponding user of i;

Step 3: each via node carries out, after two element field addition process, sending to receiving terminal to the message receiving;

Step 4: receiving terminal is by the relay message r of the each via node receiving _j, arrange in order N relay message r _jform polarization code code word, carry out polarization code decoding processing.

The present invention is by utilizing the error correction characteristic of polarization code and the diversity gain of Internet Transmission, polarization code is applied in network coding cooperation transmission neatly, reduce network channel transmission error rate, improve Internet Transmission stability, and just can obtain by a decoding information that all users send at network receiving terminal, add computing without carrying out again mould two.Avoid because a certain road decoding error adds through mould two error propagation that computing causes.

Further, in order to realize the saving of transfer resource, can consider that following measure saves network transmission resource, the first: at described generator matrix G _pl row in, the element that i is capable if having and only have is " 1 ", capable i corresponding user is directly connected with receiving terminal, in current network, cancel with l and be listed as corresponding via node, allow user directly send message to receiving terminal, and in the time that receiving terminal is carried out polarization code decoding processing, the transmission message of the user i coming from is set to corresponding to via node R _lrelay message r _l; It two is: at described generator matrix G _pin, if s row are identical with the element of t row, in current network, cancel via node R _s(via node R _sfor generator matrix G _ps be listed as corresponding via node, described via node R _tfor generator matrix G _pt be listed as corresponding via node, the via node of cancellation can be from relaying node R _swith R _tcan choose arbitrarily, normally select according to channel conditions or other actual conditions, for example, consider its channel ratio, by poor channel ratio canceling; Or the transmission range of consideration via node, by long the canceling of transmission range); , in the time that receiving terminal is carried out polarization code decoding processing, arrange corresponding to via node R _srelay message r _sequal corresponding via node R _trelay message r _t.Above-mentioned two kinds of modes both can be taked separately, also can take simultaneously.

In sum, owing to having adopted technique scheme, the invention has the beneficial effects as follows: reduced network channel transmission error rate, improved Internet Transmission stability; Can also be optimized transfer resource according to practical application request simultaneously.

Accompanying drawing explanation

Fig. 1 is network connection diagram;

Fig. 2 is the network connection diagram of embodiment 1;

Fig. 3 is that embodiment 1 optimizes resource network connection diagram after treatment;

Fig. 4 is the network connection diagram of embodiment 2;

Fig. 5 is that embodiment 2 optimizes resource network connection diagram after treatment;

Embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with execution mode and accompanying drawing, the present invention is described in further detail.

The present invention will be applied to network coding cooperation communication for the polarization code of channel error correction, its key is how according to the practical communication demand of network, polarization code parameter (N is set, K), be code word size and information bit length, for a network that has a m user, the precondition of applying the network encode collaboration communication method based on polarization code of the present invention is, via node number in network is not less than number of users, in this programme, the one-component of getting message vector due to each user is for transmitting the data of oneself, for m user, polarization code parameter K=m is set, code word size N is to should the required via node number of network, for choosing of code code word size N, if considered from the angle of saving resource, can select an Integer N to make it meet N=2 ⁿ, n be positive integer and N>=m(in the time that equal sign is set up without error correcting capability) and N be less than the minimum value of the required interstitial content of network, as error-correcting performance is had relatively high expectations, the value of N can be selected the maximum of the required via node number of network.After definite parameter (N, K), according to the building method of the existing generator matrix about polarization code, construct polarization code generator matrix G of the present invention _p, mainly comprise the following steps:

(1) by basis matrix it is done to N subdirect product and obtain G _n= , G _nit is the matrix of a N × N;

(2), according to channel transition probability, select to make Pasteur's parameter (Bhattacharyya parameter) k minimum subscript label i', forms massage set A;

(3) choose G _nin matrix, line number is a generator matrix G of row composition of all elements of massage set A _p.

Conventionally at structure massage set A, if can meet network service demand with the irrelevant polarization code of channel, can select according to erasure channel recursion method Pasteur's parameter z _1,1initial value can select 1/2; If desired construct the relevant polarization code of channel, because network condition in region is close, can select a representative link to detect its channel conditions, and the priori parameter building the transition probability of this channel as polarization code.

As the generator matrix G building for network cooperation communication _pafter, at the transmitting terminal of message, m(m=K) message bit of the every transmission of individual user, now transmitting terminal sends out K message bit altogether, and this K message bit does not send to all relayings, network connection layout as described in Figure 1, based on the network shown in Fig. 1, the generator matrix G that it is corresponding _pcan be expressed as: wherein row vector respectively user shown in corresponding diagram 11,2 ..., K, column vector is corresponding each via node respectively, relaying as shown in Figure 11,2 ..., N, the message that the received user of each via node sends is determined by the corresponding row of this relaying, as j(j=1,2,, N) and while being listed as i behavior 1, relaying j receives user i(i=1,2,, K) and the message bit that sends, if 0 does not receive (from another angle, i user by message send to i capable in element be the relaying of 1 representative, in fact network topology is G _pthe bigraph of representative).At each via node place, all message bit that receive are carried out to two element field addition (mould two adds) and sent to receiving terminal, receiving terminal to receive all relay message r ₁..., r _j... r _n(wherein r _jrepresent the message that receiving terminal receives from relaying j), reassemble into and matrix G _pcorresponding polarization code code word, corresponding each via node is at matrix G _pin put in order, by synthetic each relay message der group one receive vector ( _r1 ..., r _j... r _n) after, carry out polarization code decoding and just can obtain the message that m user sends.

In addition, based on the polarization code generator matrix of the present invention structure, can consider that following two measures save network transmission resource:

First: if at the generator matrix G of constructed polarization code _pin certain row l(l ∈ 1,2 ... N}) only having i row element is 1, can in network, remove relaying l, allows user i directly send message to receiving terminal, and in the time that receiving terminal is carried out polarization code decoding processing, the transmission message of the user i coming from is set to corresponding to via node R _lrelay message r _l.In order to consider transmission loss, conventionally the in the situation that the channel poor signal to noise by the channel of relaying and receiving terminal being apart from little (such as poor signal to noise is apart from 3dB) at the channel of user i and receiving terminal and user i, carry out this measure and save network transmission resource, to guarantee transmission quality;

Second: if generator matrix G _pin certain two column vector v _s=v _t(s, t ∈ 1,2 ... N} when and s ≠ t), can remove arbitrary via node in current network from relaying s or t, normally select according to channel conditions or other actual conditions, for example, consider its channel ratio, by poor channel ratio in both canceling; Or the transmission range of consideration via node, by long the canceling of transmission range in both, remove relaying s if suppose,, in the time that receiving terminal carries out decoding processing, s the reception component r receiving in vector is set _sequal t and receive component r _tthe decoding processing of rear execution polarization code.

Embodiment 1

Referring to Fig. 2, there is 5 users' network for a transmitting terminal, the processing procedure of constructing its network cooperation communication with polarization code is as follows:

First determine that the via node number that will use is polarization code word length N, because user's number is 5, we select N=2 ³=8(n=3) build polarization code, suppose that channel is erasure channel, probability of erasure is ε=1/2, then from by basis matrix obtain matrix , n=3 in the present embodiment, corresponding matrix is as follows:

$F^{\⊗3}=\left(\begin{array}{cccccccc}1& 0& 0& 0& 0& 0& 0& 0\\ 1& 1& 0& 0& 0& 0& 0& 0\\ 1& 0& 1& 0& 0& 0& 0& 0\\ 1& 1& 1& 1& 0& 0& 0& 0\\ 1& 0& 0& 0& 1& 0& 0& 0\\ 1& 1& 0& 0& 1& 1& 0& 0\\ 1& 0& 1& 0& 1& 0& 1& 0\\ 1& 1& 1& 1& 1& 1& 1& 1\end{array}\right)$

Then at matrix in, choose corresponding row vector and build polarization code: based on the recurrence formula of existing structure polarization code , the compute vector z of recurrence _n=(z _{n, 1}..., z _n,N), wherein k=1,2,2 ²..., 2 ^n-1, j=1,2 ..., N, when beginning, the value of giving z _1,1=ε, can calculate vectorial z ₈=(0.996,0.684,0.809,0.121,0.879,0.191,0.316,0.004), then build displacement π according to arranging from small to large ₈=(8,4,6,7,2,3,5,1), the Vector Groups of therefore choosing corresponding row becomes polarization code (N, K)=(8,5), obtains generator matrix G _p(8,5):

$G_P\left(\mathrm{8,5}\right)=\left[\begin{array}{cccccccc}1& 1& 0& 0& 0& 0& 0& 0\\ 1& 1& 1& 1& 0& 0& 0& 0\\ 1& 1& 0& 0& 1& 1& 0& 0\\ 1& 0& 1& 0& 1& 0& 1& 0\\ 1& 1& 1& 1& 1& 1& 1& 1\end{array}\right]$

Generator matrix G based on obtained _p(8,5) carry out optimizing transmission resource processing to current network, because at generator matrix G _p(8,5) in the 8th row, only the element of the 5th row is " 1 ", user 5 directly can be connected with receiving terminal, cancel relaying 8(as shown in Figure 3), each via node carries out the reception & disposal of information based on generator matrix and sends to receiving terminal, and receiving terminal is in the time carrying out polarization code decoding processing, according to putting in order of 8 relayings in matrix, by the relay message r of relaying 1～8 ₁～r ₈arrange in order, be combined into one and receive vector (r ₁, r ₂, r ₃, r ₄, r ₅, r ₆, r ₇, r ₈), because in the time that optimizing transmission resources is processed, cancelled relaying 8, arrange and receive vectorial r ₈for the message from user 5 of obtaining, then carry out polarization code decoding processing to receiving vector.

Embodiment 2

Current network connects as shown in Figure 4, comprises 3 users, and 8 via nodes (relaying 1～8) obtain corresponding generator matrix based on polarization code building method of the present invention and are , and transfer resource is optimized to processing, at generator matrix G _pin (8,3), because the 5th row are identical with the 1st row, the 6th row are identical with the 2nd row, and the 7th row are identical with the 3rd row, and the 8th row are identical with the 4th row, therefore can consider in four groups (1,5), (6,2), (7,3), in (8,4), only retain a via node in every group, in the present embodiment, select to retain relaying 1,2,3,4 based on signal to noise ratio, and, again because generator matrix G _pin the 4th row of (8,3), only the element of the 3rd row is 1, therefore delete relaying 4, user 3 is directly connected with receiving terminal, and the network after optimization connects as shown in Figure 5.In the time that receiving terminal is carried out decoding processing, to receiving vector (r ₁..., r ₈) in r ₅～r ₈arrange as follows: , wherein r ₁, r ₂, r ₃for the relay message directly receiving from relaying 1,2,3 correspondences, r ₄for the user message directly receiving from user 4; After setting completes, then based on generator matrix G _p(8,3) are to receiving vector (r ₁..., r ₈) execution polarization code decoding processing.

The above, be only the specific embodiment of the present invention, and arbitrary feature disclosed in this specification, unless narration especially all can be replaced by other equivalences or the alternative features with similar object; Step in disclosed all features or all methods or process, except mutually exclusive feature and/or step, all can be combined in any way.

Claims (5)

1. the network encode collaboration communication method based on polarization code, is characterized in that, comprises the following steps:

Step 1: structure polarization code generator matrix G _p:

Determine hyper polarization code parameters N, K, wherein, N represents code word size, K represents information bit length:

Described polarization code Parameter N is more than or equal to user's number m and is less than the minimum value of network demand via node number, and N=2 ⁿ, n is positive integer;

Described polarization code parameter K equals user's number m;

And user's number m is less than or equal to the via node number of current network;

Based on described polarization code Parameter N, K structure polarization code generator matrix G _p, described matrix G _pthe corresponding via node of every row, the corresponding user of every a line;

Step 2: each via node is based on matrix G _preceive the information that respective user sends: as matrix G _pwhen j is listed as i behavior " 1 ", is listed as corresponding via node with j and receives the message sending with the capable corresponding user of i;

Step 3: each via node carries out, after two element field addition process, sending to receiving terminal to the message receiving;

Step 4: receiving terminal is by the relay message r of the each via node receiving _j, arrange in order N relay message r _jform polarization code code word, carry out polarization code decoding processing.

2. the method for claim 1, is characterized in that, described polarization code Parameter N is the maximum of network demand via node number, and N=2 ⁿ, n is positive integer.

3. the method for claim 1, is characterized in that, in described step 1, at described generator matrix G _pl row in, the element that r is capable if having and only have be " 1 ", capable i corresponding user i is directly connected with receiving terminal, in current network, cancellation and l are listed as corresponding via node R _l;

, in described step 4, in the time that polarization code decoding is processed, the transmission message of the user i coming from is set to corresponding to via node R _lrelay message r _l.

4. the method as described in claim 1,2 or 3, is characterized in that, in described step 1, at described generator matrix G _pin, if s row are identical with the element of t row, in current network, cancel via node R _s;

, in described step 4, in the time that polarization code decoding is processed, arrange corresponding to via node R _srelay message r _sequal corresponding via node R _trelay message r _t;

Described via node R _sfor generator matrix G _ps be listed as corresponding via node, described via node R _tfor generator matrix G _pt be listed as corresponding via node.

5. method as claimed in claim 4, is characterized in that, described in the via node R that is cancelled _sfor via node R _sand R _tin, the via node that the transmission range of user and relaying and/or relaying and receiving terminal is grown;

Or described in the via node R that is cancelled _sfor via node R _sand R _tthe via node that middle channel ratio is poor.